Anti-squeal pad for a brake disc, a disc brake assembly and a lightweight vehicle with a brake disc with such Anti-squeal pad

Abstract

The invention relates to an anti-squeal pad for brake discs of a lightweight vehicle such as bicycles, scooters and possibly motorcycles and low-speed cars. The anti-squeal pad is attached to the brake disc, or the anti-squeal pad constitute an integrate part of the brake disc. The anti-squeal pad comprises a constrained layer damping (CLD) pad with at least one metallic layer and at least one viscoelastic layer for attaching the pad to a side surface of parts the brake disc or for inserting between parts of the brake disc. The invention also relates to a brake disc and to a disc brake assembly with such anti-squeal pad and to a vehicle with such disc brake assembly.

Description

[0001] ANTI-SQUEAL PAD FOR A BRAKE DISC, A DISC BRAKE ASSEMBLY AND

[0002] A LIGHTWEIGHT VEHICLE WITH A BRAKE DISC WITH SUCH ANTI-SQUEAL PAD

[0003] FIELD OF THE INVENTION

[0004] The invention relates to a brake disc for a disc brake assembly for a lightweight vehicle such as bicycles, electric scooters, and fossil fuel-powered scooters and possibly also electric or fossil fuel-powered motorcycles, but not for cars, trucks, busses, and other relatively larger vehicles.

[0005] The brake disc has a hub at an inner section of the brake disc and has spokes or an annular shaped extension extending between the hub and an outer section of the brake disc. The outer section extends in extension of the spokes or the annularly shaped extension and constitute a brake surface of the brake disc, where brake pads of a brake caliper of a disc brake assembly is intended for clutching the brake disc during braking.

[0006] Disc brake assemblies of bicycles and other lightweight vehicles are known to occasionally produce a squealing noise during braking. The noise is very annoying to the driver of the vehicle and to others in the vicinity of the vehicle.

[0007] Known solutions are to exchange brake pads of the disc brake assembly with new brake pads or to shape and dimension the brake disc according to known or new standards. However, once the bicycle or other lightweight vehicle has been taken into use, it is the user who has to remedy the problems of the squealing noise. This may be expensive for the owner of the vehicle, or the solutions may not be enough to remedy the problem.

[0008] US 2017 / 0259874 Al discloses, among other embodiments, in Fig. 32-39, a damper assembly removably supported between a disc brake rotor and a plurality of spokes as a separate component. The damper assembly is configured to apply a first damping force, in the embodiment a first axial damping force Fl, against the spoke segment of at least one spoke of the plurality of spokes and a rotor damping force, in this embodiment a rotor axial damping force FR, against the disc brake rotor (see Fig. 35). The axial force and rotor damping forces may be applied in various directions such as axial and / or tangential.

[0009] The damper assembly in US 2017 / 0259874 Al is designed for a specific hub of a wheel, for a specific configuration of spokes of the wheel and must be installed during assembly of the wheel, that is, on the place of manufacture of the wheel, alternatively by a bicycle repair shop or by a bicycle owner being skilled in dismantling and reassembling a bicycle wheel, that is, a bicyde owner being more than averagely skilled.

[0010] An object of the invention may be for an owner of a bicycle or lightweight vehicle to be able to remedy the problem of a squealing sound in an easy and reliable manner without having to buy expensive new brake discs and / or new brake pads and having to exchange these parts and not having to dismantle and reassemble a bicycle wheel.

[0011] Another object of the invention may be to ensure that the squealing sound is avoided during braking, depending on the shape of, the dimension of and the make of the disc brake assembly as a whole, that is, the brake disc, the brake pads, the brake caliper, mounting of the brake disc to a hub of a wheel, mounting of the brake caliper to a frame and other factors possibly leading to a squealing noise emitted during braking.

[0012] SUMMARY OF THE INVENTION

[0013] The object of the invention may be obtained by an anti-squeal pad for a brake disc of a disc brake assembly, the anti-squeal pad comprising a constrained layer damping pad with at least one metallic layer and at least one viscoelastic layer, and the pad having a shape configured to a selected section of a shape of the brake disc onto which the pad is to be attached, the shape of the pad being at least one of the following shapes:

[0014] - a shape of an inner section of the brake disc, the shape of the pad as the inner section of the brake disc corresponding to the inner section outside possible holes for attaching the brake disc to a wheel of the lightweight vehicle,

[0015] - a shape of an inner section of the brake disc, the shape of the pad as the inner section of the brake disc having holes corresponding to holes of the brake disc for attaching the brake disc to a wheel of the lightweight vehicle,

[0016] - a shape of a middle section of the brake disc, the middle section extending between the inner section and an outer section of the brake disc, the outer section of the brake disc constituting a brake surface of the brake disc

[0017] - a shape of an outer section (8) of the brake disc, the outer section (8) extending circumferentially along an outside circumference of the middle section (5), the outer section (8) of the brake disc constituting a brake surface of the brake disc (1).

[0018] Attaching an anti-squeal pad of a constrained damping layer pad with at least one metallic layer and at least one viscoelastic layer for attaching the pad to a side surface of the brake disc result in the possible squeal from the brake disc during braking is limited or even eliminated. Another advantage is that the anti-squeal pad may be configured to the size and shape of various brake discs and may be attached subsequently to the manufacture of the brake disc and subsequently to assembling the lightweight vehicle.

[0019] Spokes of a brake disc may have different shapes between the inner section and the outer section of the brake disc. Each of the spokes have a selected shape between inner section and the outer section of the brake disc, and between the leading edge and the trailing edge the brake disc depending on various other parameters. Inner sections and outer section of brake discs may also have different shapes depending on the wheel onto whish the brake disc is to be attached and depending on various other parameters.

[0020] The selected shape of spokes, of inner sections and of outer sections depends on the size of the brake disc, depends on the forces to be applied to the brake disc, and may also depend on visual appearance of the brake disc. The shape of the brake disc depends on the type of lightweight vehicle the brake disc is intended for, that is, a relatively heavy or light vehicle and / or a relatively fast-going or slow-going vehicle. The shape of the spokes also depends on the selected shape by the manufacturer of the brake disc.

[0021] According to one embodiment of an anti-squeal pad according to the invention, the shape of the pad is as a hub constituting the inner section of the brake disc, and where the shape of the pad also is as a shape of a plurality of spokes, preferably all spokes, constituting part of the middle section of the brake disc.

[0022] The pad having a shape of, and intended for being attached to, both the hub of the brake disc and one or more spokes of the brake disc result in the pad limiting or eliminating possible squeal induces both in, or either in, the hub and the spokes of the brake disc during braking of the lightweight vehicle.

[0023] According to another embodiment of an anti-squeal pad according to the invention, the shape of the pad only is as a hub constituting the inner section of the brake disc, and the shape of the pad is exclusive of a shape of a plurality of spokes constituting part of the middle section of the brake disc.

[0024] The pad having a shape of, and intended for being attached to, only the hub of the brake disc result in the pad being securely attached to the brake disc via attachment means for attaching the brake disc to a wheel of the lightweight vehicle while at the same time limiting or eliminating possible squeal induces only in the hub of the brake disc during braking of the lightweight vehicle, if squeal is found to be induced only in the hub. According to yet another embodiment of an anti-squeal pad according to the invention, the pad has a shape as both the hub constituting the inner section of the brake disc and a plurality of spokes, preferably all spokes, constituting part of the middle section of the brake disc and a plurality of void spaces, preferably all void spaces, in the brake disc, between the plurality of spokes of the brake disc and also constituting part of the middle section of the brake disc.

[0025] The pad having a shape of, and intended for being attached to, both the hub of the brake disc and one or more spokes of the brake disc and even void spaces between the spokes result in the pad being securely attached to the brake disc via attachment means for attaching the brake disc to a wheel of the lightweight vehicle while at the same time limiting or eliminating possible squeal induces in the spokes of the brake disc during braking of the lightweight vehicle, but the pad need not be shaped according to a shape and dimension of the spokes of the brake disc, because the pad covers all the spokes together with void spaces between the spokes, the pad having a shape of a disc.

[0026] According to yet another embodiment of an anti-squeal pad according to the invention, the pad has a plurality of holes extending through the pad, the plurality of holes intended for allowing bolts or rivets to pass through the pad and into a corresponding plurality of holes in the brake disc, for attaching the brake disc to a wheel of the vehicle.

[0027] The pad having holes corresponding to the holes for attaching the brake disc to a wheel of the vehicle result in the pad being more securely attached to the brake disc with the rivets or bolts for attaching the brake disc to the wheel, than possibly just attaching the pad by an adhesive to the inner section and / or the middle section of the brake disc.

[0028] According to a preferred embodiment of an anti-squeal pad according to the invention, the pad is made of at least the following layers: a metallic layer having a thickness between 0.1 mm and 6.0 mm, possibly between 0.1 mm and 3.0 mm or between 0.1 mm and 1.0 mm, and a viscoelastic layer having a thickness between 0.01 mm and 2.0 mm, possibly between 0.01 mm and 0.5 mm or between 0.05 mm and 0.2 mm,

[0029] - the metallic layer intended for facing away from the brake disc, compared to an orientation of the viscoelastic layer, when the pad is attached to the brake disc, and

[0030] - the viscoelastic layer intended for facing towards the brake disc, compared to an orientation of the metallic layer, when the pad is attached to the brake disc.

[0031] According to a possible embodiment of an anti-squeal pad according to the invention, the viscoelastic layer consists of at least two components configured as individual component layers of the viscoelastic layer, the at least two component layers being a first layer of an adhesive material and at least one second layer of a material selected among an elastomeric material and an adhesive material, and the first layer of adhesive material intended for being attached to the metallic layer of the brake disc when the pad is attached to the brake disc, and the at least one second layer intended for facing away from the metallic layer of the brake disc when the pad is attached to the brake disc.

[0032] The object of the invention may also be obtained by a brake disc for a lightweight vehicle, the brake disc having a hub along an inner section of the brake disc, spokes extending between the hub and an outer section of the brake disc, the brake disc having an anti-squeal pad attached to an outer surface of one of the following sections of the brake disc: At least part of the inner section or at least part of the middle section or at least part of both the inner section and the middle section.

[0033] The object of the invention may also be obtained by a brake disc for a lightweight vehicle, the brake disc having a hub along an inner section of the brake disc, spokes extending between the hub and an outer section of the brake disc, one of the following sections of the brake disc: Part of the inner section or at least part of the middle section or both the inner section and at least part of the middle section comprising an antisqueal pad being integrate with an outer surface of the brake disc part.

[0034] According to an embodiment of a brake disc according to the invention, the brake disc has a hub along an inner section of the brake disc, a middle section extending between the hub an outer section of the brake disc, the brake disc being made by at least the following layers:

[0035] - a first metallic layer having a thickness between 0.1 mm and 6.0 mm, possibly between 0.1 mm and 3.0 mm or between 0.1 mm and 1.0 mm,

[0036] - a viscoelastic layer having a thickness between 0.01 mm and 2.0 mm, possibly between 0.01 mm and 0.5 mm or between 0.05 mm and 0.2 mm, and

[0037] - a second metallic layer having a thickness between 0.1 mm and 6.0 mm, possibly between 0.1 mm and 3.0 mm or between 0.1 mm and 1.0 mm, and

[0038] - where the viscoelastic layer is placed between the first metallic layer and the second metallic layer.

[0039] According to an embodiment of a brake disc according to the invention, the middle section of the brake disc has one of the following shapes of the middle section of the brake disc: a plurality of spokes extending between the inner section and an outer section of the brake disc and a plurality of void spaces between the spokes and extending between the inner section and the outer section of the brake disc, or an annular shape extending between the inner section and the outer section of the brake disc.

[0040] The object of the invention may also be obtained by a disc brake assembly for a lightweight vehicle, the disc brake assembly having a brake caliper with brake pads and a brake disc, the brake pads intended for clutching a brake section of the brake disc during braking, and the brake disc having an anti-squeal pad attached to at least one of the following sections of the brake disc: The inner section or part of the middle section or to both the inner section and part of the middle section.

[0041] The object of the invention may also be obtained by a lightweight vehicle with at least one wheel and having at least one disc brake assembly according to the invention with the brake disc attached to the at least one wheel.

[0042] The invention reduces the risk of excitation of modes in a disc brake assembly by increasing the modal damping of a brake disc. By increasing the modal damping, the stability of the complex eigenfrequencies of the system is improved. Thus, making friction-induced vibrations less likely to occur.

[0043] BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Fig. 1A and IB show a brake disc and a first embodiment of constrained layer damping pads according to the invention,

[0045] Fig. 1C shows a brake disc and an alternative first embodiment of constrained layer damping pads according to the invention,

[0046] Fig. 2A and 2B show a brake disc and a second embodiment of constrained layer damping pads according to the invention,

[0047] Fig. 3A and 3B show a brake disc and a third embodiment of constrained layer damping pads according to the invention,

[0048] Fig. 4A and 4B show a brake disc and a fourth embodiment of constrained layer damping pads according to the invention,

[0049] Fig. 5 shows a brake disc with constrained layer damping material integrated into the brake disc as part of the brake disc, and

[0050] Fig. 6A and fig. 6B show a brake disc with constrained layer damping material integrated into only a part of the brake disc as part of the brake disc. DETILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0051] Fig. 1A and Fig. IB show a first embodiment of a constrained layer damping pad, in the following abbreviated CLD pad, for a bicycle brake disc of a bicycle disc brake assembly. In the embodiment shown in fig. 1A and fig. IB, the pad has a star-like shape.

[0052] In the following, a bicycle and a bicycle wheel and a disc brake assembly and a brake disc for a bicycle wheel are used as an example of a lightweight vehicle for which the CLD pads are intended to be used. However, this example is not limiting the scope of use of the CLD pads. Other lightweight vehicles may be electric scooters and fossil fuel- powered scooters and possibly also electric or fossil fuel-powered motorcycles.

[0053] A brake disc 1 itself, without the constrained layer damping pad attached, is known per se, not in itself constituting part of the invention. The brake disc 1 has an inner section 2 constituting a hub 3 of the brake disc 1, the hub 3 intended for being attached to a hub of a bicycle wheel (not shown) by bolts or rivets (not shown) inserted through holes 4 in the hub of brake disc 1 and through holes in the hub of the wheel.

[0054] The brake disc 1 also has a middle section 5 extending between the inner section 2 and an outer section. In the embodiment of the brake disc 1 shown, the middle section 5 is constituted by a plurality of spokes 6, eight spokes in total. In the figure, the spokes 6 extend outwards from the hub 3 to outer ends 7 of the spokes 6. The spokes 6 extend obliquely to a radial direction, when viewed in a plane of the brake disc 1. The oblique extension is forwards in relation to a rotational direction R, during bicycling, of the bicycle wheel which the brake disc 1 is to be attached to. In an alternative embodiment of the brake disc the middle section 5 is constituted by an annularly shaped extension.

[0055] Each of the spokes 6 has a radial extension between the inner section 2 and the outer section 8 of the brake disc 1. Each of the spokes 6 also has a tangential extension between a leading edge 6A and a trailing edge 6B of the spokes 6, in relation to a predominant rotational direction R of the brake disc 1 when attached to a wheel of a vehicle. Each of the spokes 6 basically has a shape dependant on a selected shape by the manufacturer of brake disc 1, the selected shape dependant on various parameters such as size, strength, weight and possibly also visual appearance of the brake disc.

[0056] The brake disc 1 furthermore has an outer section 8. The outer section 8 extends from the outer ends 7 of the spokes 6. The outer section 8 constitutes a brake surface of the brake disc 1, where brake pads (not shown) of a brake caliper (not shown) are to clutch the brake disc 1 during braking. The brake surface is provided with holes 9 of various size and shape. The holes are for cooling the brake section during braking and / or for accumulation of dirt possibly collecting on the brake surface during bicycling.

[0057] Fig. IB shows CLD pads 10,11 attached to both side surfaces of the brake disc 1, on the hub 3 constituting the inner section 2 of the brake disc 1 and on both side surfaces of all eight spokes 6 constituting the middle section 5 of the brake disc 1. In alternative embodiments, one CLD pad 10,11 is attached only to one of the side surfaces of the brake disc 1, either one CLD pad 10 on the one side surface or one CLD pad 11 on the other opposite side surface.

[0058] Fig. 1A shows the CLD pads 10,11 when attached to the brake disc 1 and Fig. IB shows the CLD pads 10,11 before being attached to the brake disc 1. In the embodiment shown, each of the CLD pads 10,11 for each side of the brake disc 1 has the same shape, a shape corresponding to the combined shape of the hub 3 constituting the inner section 2 of the brake disc 1 and the eight spokes 6 constituting the middle section 5 of the brake disc 1.

[0059] Each of the CLD pads has a radial extension B, extending from an imaginary centre A of the CLD pad, and corresponding to a centre of a wheel which the brake disc is to be attached to, towards and to an outer boundary of the CLD pads. The radial extension B may be between 50 mm and 200 mm, possibly between 25 mm and 75 mm, possibly between 50 mm and 100 mm, dependant on the shape and size of the brake disc 1, including the shape and size of the hub 3 and of the spokes 6 of the brake disc 1.

[0060] Each of the CLD pads has a tangential extension C in the rotational direction of a wheel which the brake disc is to be attached to and corresponding to a width of the spokes 6 between a trailing edge 6A and a leading edge 6B of the spokes 6. The tangential extension C may be between 3 mm and 50 mm, dependant on the shape and size of the brake disc 1, including the shape and size of the spokes 6 of the brake disc 1.

[0061] Other shapes of the CLD pads 10 are shown in the following figures. Possibly, a CLD pad 10 of one shape may be attached to one side surface of the brake disc 1 and another CLD pad 11 of another shape may be attached to another side surface of the brake disc 1.

[0062] The CLD pads 10,11 has an inner section 12 and eight outwards extending sections 13 extending outwards from the inner section 12. The inner section 12 of the CLD pads 10,11 corresponds to the shape of the hub 3 of inner section 2 of the brake disc 1, including holes 14 as in the inner section 2 of the brake disc 1, for bolts or rivets for attaching the brake disc 1 to the hub of the bicycle. In the embodiment shown, the outwards extending sections 13 of the CLD pads 10,11 correspond in number, that is eight, and in shape, to the number of and the shape of the spokes 6 of the brake disc 1.

[0063] In alternative embodiments, the number of outwards extending sections 13 of the CLD pads 10,11 may be less than eight, possibly only four, so that possibly only every second spoke 6 of the brake disc 1 has part of a CLD pad 10,11 attached. The distance which the outwards extending sections 12 extend may be less than a length of the spokes 6, if perhaps a shorter extension of the outwards extending sections 13 of the CLD pads 10,11 is sufficient to obtain satisfactory squeal attenuation during braking.

[0064] The number of outwards extending sections 13 of the CLD pads 10,11 and the shape and extension of the outward extending sections 13 of the CLD pads 10,11 may also be selected depending on a need for a certain number of, and a need for a certain shape of, CLD pads 10,11 on the middle section 5 of the brake disc 1, while still obtaining satisfactory squeal attenuation during braking.

[0065] Fig. 1C shows an alternative first embodiment. The CLD pad is for most parts identical to the CLD pads shown in Fig. 1A and Fig. IB and also has a star-like shape.

[0066] In the alterative embodiment shown in Fig. 1C, the CLD pads 10,11 (only one CLD pad 10 shown) extend beyond on or more holes (not shown) in the spokes 6 of the brake disc. The CLD pads in the embodiment shown in Fig. 1C have holes (not shown) at an outermost extension of the CLD pads, each of which holes correspond to one hole in each of the spokes. The CLD pads, when attached by means of an adhesive to the spokes 6 of the brake disc 1 are further secured to the brake disc 1 by rivets 15 or bolts extending through each of the holes in the outermost extension of the CLD pads and through the corresponding holes in the spokes 6 of the brake disc 1. Thereby, the CLD pads are more safely secured to the brake disc 1 than just by an adhesive. In the embodiment shown, the CLD pads are secured by rivets or bolts both at the hub 3 of the inner section 2 of the brake disc 1 and at a radially outermost extension of the middle section 5 of the brake disc 1.

[0067] Fig. 2A and Fig. 2B show a second embodiment of a constrained layer damping pad, in the following abbreviated CLD pad, for a bicycle brake disc of a bicycle disc brake assembly. In the embodiment shown in fig. 2A and fig. 2B, the pad consists of a plurality of pads having an elongated shape, each pad corresponding to a shape of a spoke 6.

[0068] A brake disc 1 itself, without the CLD pad attached, is known per se, not in itself constituting part of the invention. The brake disc 1 has an inner section 2 constituting a hub 3 of the brake disc 1, the hub 3 intended for being attached to a hub of a bicycle wheel (not shown) by bolts or rivets (not shown) inserted through holes 4 in the hub of brake disc 1 and through holes in the hub of the wheel.

[0069] The brake disc 1 also has a middle section 5 extending between the inner section 2 and an outer section. In the embodiment of the brake disc 1 shown, the middle section 5 is constituted by a plurality of spokes 6, eight spokes in total. In the figure, the spokes 6 extend outwards from the hub 3 to outer ends 7 of the spokes 6. The spokes 6 extend obliquely to a radial direction, when viewed in a plane of the brake disc 1. The oblique extension is forwards in relation to a rotational direction R, during bicycling, of the bicycle wheel which the brake disc 1 is to be attached to. In an alternative embodiment of the brake disc the middle section 5 is constituted by an annularly shaped extension.

[0070] Each of the spokes 6 has a radial extension between the inner section 2 and the outer section 8 of the brake disc 1. Each of the spokes 6 also has an extension between a leading edge 6A and a trailing edge 6B of the spokes 6, in relation to a predominant rotational direction R of the brake disc 1 when attached to a wheel of a vehicle. Each of the spokes 6 basically has a shape dependant on a selected shape by the manufacturer of brake disc 1, the selected shape dependant on various parameters such as size, strength, weight and possibly also visual appearance of the brake disc.

[0071] The brake disc 1 furthermore has an outer section 8. The outer section 8 extends from the outer ends 7 of the spokes 6. The outer section 8 constitutes a brake surface of the brake disc 1, where brake pads (not shown) of a brake caliper (not shown) are to clutch the brake disc 1 during braking. The brake surface is provided with holes 9 of various size and shape. The holes are for cooling the brake section during braking and / or for accumulation of dirt possibly collecting on the brake surface during bicycling.

[0072] Fig. 2B shows a plurality of CLD pads 15,16 attached to both side surfaces of the brake disc 1, on both side surfaces of all eight spokes 6 constituting the middle section 5 of the brake disc 1. In alternative embodiments, CLD pads 15,16 are attached only to one of the side surfaces of the brake disc 1, either a plurality of CLD pads 15 on the one side surface or a plurality of CLD pads 15 on the other opposite side surface. Fig. 2A shows the CLD pads 15,16 when attached to the brake disc 1 and Fig. 2B shows the CLD pads 15,16 before being attached to the brake disc 1. In the embodiment shown, each of the CLD pads 15,16 for each side of the brake disc 1 has the same shape, a shape corresponding to the eight spokes 6 constituting the middle section 5 of the brake disc 1. Possibly, CLD pads 15 of one shape may be attached to one side surface of the brake disc 1 and other CLD pads 16 of another shape may be attached to the other side surface of the brake disc 1.

[0073] The CLD pads 15,16 constitute eight outwards extending sections. In the embodiment shown, the CLD pads 15,16 correspond in number, that is eight, and in shape, to the number of and the shape of the spokes 6 of the brake disc 1.

[0074] Each of the CLD pads has a radial extension B, extending from an imaginary centre A of the CLD pad, and corresponding to a centre of a wheel which the brake disc is to be attached to, towards and to an outer boundary of the CLD pads. The radial extension B may be between 25 mm and 200 mm, possibly between 25 mm and 75 mm, possibly between 50 mm and 100 mm, dependant on the shape and size of the brake disc 1, including the shape and size of the spokes 6 of the brake disc 1.

[0075] Each of the CLD pads has a tangential extension C in the tangential direction of a wheel which the brake disc is to be attached to and corresponding to a width of the spokes 6 between a trailing edge 6A and a leading edge 6B of the spokes 6. The tangential extension C may be between 3 mm and 50 mm, dependant on the shape and size of the brake disc 1, including the shape and size of the spokes 6 of the brake disc 1.

[0076] In alternative embodiments, the number of CLS pads 15,16 may be less than eight, possibly only four, so that possibly only every second spoke 6 of the brake disc 1 has a CLD pad 15,16 attached. The distance which the outwards extending sections 12 extend may be less than a length of the spokes 6, if perhaps a shorter extension of the CLD pads 15,16 is sufficient to obtain satisfactory squeal attenuation during braking.

[0077] Fig. 3A and Fig. 3B show a third embodiment of a constrained layer damping pad, in the following abbreviated CLD pad, for a bicycle brake disc of a bicycle disc brake assembly. In the embodiment shown in fig. 3A and fig. 3B, the pad has a disc-like shape.

[0078] A brake disc 1 itself, without the CLD pad attached, is known per se, not in itself constituting part of the invention. The brake disc 1 has an inner section 2 constituting a hub 3 of the brake disc 1, the hub 3 intended for being attached to a hub of a bicycle wheel (not shown) by bolts or rivets (not shown) inserted through holes 4 in the hub of brake disc 1 and through holes in the hub of the wheel.

[0079] The brake disc 1 also has a middle section 5 extending between the inner section 2 and an outer section. In the embodiment of the brake disc 1 shown, the middle section 5 is constituted by a plurality of spokes 6, eight spokes in total. In the figure, the spokes 6 extend outwards from the hub 3 to outer ends 7 of the spokes 6. The spokes 6 extend obliquely to a radial direction, when viewed in a plane of the brake disc 1. The oblique extension is forwards in relation to a rotational direction R, during bicycling, of the bicycle wheel which the brake disc 1 is to be attached to. In an alternative embodiment of the brake disc the middle section 5 is constituted by an annularly shaped extension.

[0080] The brake disc 1 furthermore has an outer section 8. The outer section 8 extends from the outer ends 7 of the spokes 6. The outer section 8 constitutes a brake surface of the brake disc 1, where brake pads (not shown) of a brake caliper (not shown) are to clutch the brake disc 1 during braking. The brake surface is provided with holes 9 of various size and shape. The holes are for cooling the brake section during braking and / or for accumulation of dirt possibly collecting on the brake surface during bicycling.

[0081] Fig. 3B shows CLD pads 17,18 attached to both side surfaces of the brake disc 1, on the hub 3 constituting the inner section 2 of the brake disc 1 and on both side surfaces of all eight spokes 6 constituting the middle section 5 of the brake disc 1. In alternative embodiments, one CLD pad 19,20 is attached only to one of the side surfaces of the brake disc 1, either one CLD pad 19 on the one side surface or one CLD pad 20 on the other opposite side surface.

[0082] Fig. 3A shows the CLD pads 17,18 when attached to the brake disc 1 and Fig. 3B shows the CLD pads 17,18 before being attached to the brake disc 1. In the embodiment shown, each of the CLD pads 10,11 for each side of the brake disc 1 has the same shape, a shape corresponding to the combined shape of the hub 3 constituting the inner section 2 of the brake disc 1 and the eight spokes 6 constituting the middle section 5 of the brake disc 1 and a void space between the spokes 6, thereby having a shape of a disc.

[0083] Each of the CLD pads has a radial extension B, extending from an imaginary centre A of the CLD pad, and corresponding to a centre of a wheel which the brake disc is to be attached to, towards and to an outer boundary of the CLD pads. The radial extension B may be between 25 mm and 200 mm, possibly between 25 mm and 75 mm, possibly between 50 mm and 100 mm, dependant on the shape and size of the brake disc 1, including the shape and size of the spokes 6 of the brake disc 1.

[0084] Each of the CLD pads has an extension in the tangential direction of a wheel which the brake disc is to be attached to and corresponding to an entire circumference of the spokes 6 and of the void spaces between the spokes 6.

[0085] Fig. 4A and Fig. 4B show a fourth embodiment of a constrained layer damping pad, in the following abbreviated CLD pad, for a bicycle brake disc of a bicycle disc brake assembly. In the embodiment shown in fig. 4A and fig. 4B, the pad has an annular shape.

[0086] A brake disc 1 itself, without the CLD pad attached, is known per se, not in itself constituting part of the invention. The brake disc 1 has an inner section 2 constituting a hub 3 of the brake disc 1, the hub 3 intended for being attached to a hub of a bicycle wheel (not shown) by bolts or rivets (not shown) inserted through holes 4 in the hub of brake disc 1 and through holes in the hub of the wheel.

[0087] The brake disc 1 also has a middle section 5 extending between the inner section 2 and an outer section. In the embodiment of the brake disc 1 shown, the middle section 5 is constituted by a plurality of spokes 6, eight spokes in total. In the figure, the spokes 6 extend outwards from the hub 3 to outer ends 7 of the spokes 6. The spokes 6 extend obliquely to a radial direction, when viewed in a plane of the brake disc 1. The oblique extension is forwards in relation to a rotational direction R, during bicycling, of the bicycle wheel which the brake disc 1 is to be attached to. In an alternative embodiment of the brake disc the middle section 5 is constituted by an annularly shaped extension.

[0088] The brake disc 1 furthermore has an outer section 8. The outer section 8 extends from the outer ends 7 of the spokes 6. The outer section 8 constitutes a brake surface of the brake disc 1, where brake pads (not shown) of a brake caliper (not shown) are to clutch the brake disc 1 during braking. The brake surface is provided with holes 9 of various size and shape. The holes are for cooling the brake section during braking and / or for accumulation of dirt possibly collecting on the brake surface during bicycling.

[0089] Fig. 4B shows CLD pads 19,20 attached to both side surfaces of the brake disc 1, on the hub 3 constituting the inner section 2 of the brake disc 1. In alternative embodiments, one CLD pad 19,20 is attached only to one of the side surfaces of the brake disc 1, either one CLD pad 19 on the one side surface or one CLD pad 18 on the other opposite side surface.

[0090] Fig. 4A shows the CLD pads 19,20 when attached to the brake disc 1 and Fig. 4B shows the CLD pads 19,20 before being attached to the brake disc 1. In the embodiment shown, each of the CLD pads 19,20 for each side of the brake disc 1 has the same shape, a shape corresponding to the hub 3 constituting the inner section 2 of the brake disc 1.

[0091] The CLD pads 19,20 constitute an inner section. The shape of the CLD pads 19,20 corresponds to the shape of the hub 3 of inner section 2 of the brake disc 1, including holes 14 as the holes 4 in the inner section 2 of the brake disc 1, for bolts or rivets for attaching the brake disc 1 to the hub of the bicycle. In the embodiment shown.

[0092] Each of the CLD pads has a radial extension B, extending from an imaginary centre A of the CLD pad, and corresponding to a centre of a wheel which the brake disc is to be attached to, towards and to an outer boundary of the CLD pads. The radial extension B may be between 25 mm 200 mm, possibly between 25 mm and 75 mm, possibly between 50 mm and 100 mm, dependant on the shape and size of the brake disc 1, including the shape and size of the hub 3.

[0093] Each of the CLD pads has an extension in the circumferential direction of a wheel which the brake disc is to be attached to, corresponding to an entire circumference of the hub 3, correlating to an entire circumference of a hub of the wheel which the brake disc is to be attached to.

[0094] The shape of the CLD pads 19,20 may be selected depending on a need for a certain shape of the CLD pads 19,20 on the inner section of the brake disc 1, while still obtaining satisfactory squeal attenuation during braking.

[0095] For all embodiments shown, the CLD pads 10,11 are made from at least one metallic layer and at least one viscoelastic layer. The metallic layer is facing away from the brake disc 1, and the viscoelastic layer is facing towards the brake disc 1. The metallic layer is preferably made from stainless steel with a thickness between 0.1 mm and 2 mm. In the embodiment shown, the metallic layer has a thickness of 0.4 mm.

[0096] Fig. 5 shows a fifth embodiment of a brake disc 1, where a CLD material (not visible) is placed between two individual parts of the brake disc 1, that is, between two individual parts both having the inner section (2) constituting the hub (3) of the brake disc 1, the middle section (5) constituting the spokes of the brake disc 1 and the outer section (8) constituting the brake surface of the brake disc 1.

[0097] Each of the two individual parts of the brake disc 1 constitute a metallic disc. In-between the two metallic disc parts, the CLD pad is placed, and the two metallic disc parts with the CLD pads placed there-between are mutually joined by the viscoelastic material. Thereby, the metallic disc parts and the CLD pad constitute a brake disc 1 as such, where the CLD pad is an integrate part of the brake disc 1, initially during and subsequently after manufacture of the brake disc 1, and the CLD pad is not a part separate from the brake disc 1, attached to the brake disc 1 subsequently to manufacture of the brake disc 1 as in the previous embodiments.

[0098] In the embodiment shown in Fig. 5, the brake disc 1 is constituted by two individual metallic disc parts and one CLD pad placed between the two metallic disc parts. In alternative embodiment, the brake disc 1 is made from more than two metallic disc parts, as example three metallic disc parts, and more than one CLD pad, as example two CLD pads, placed between the three metallic disc parts, one CLD pad paced between one outermost metallic disc part and a centre metallic or non-metallic disc part, and another CLD pad placed between the centre disc part and another outermost metallic disc part.

[0099] In yet an alternative embodiment, the brake disc 1 is made from one disc part and two CLD pads placed on each of side surfaces of the one disc part. In such embodiment, the CLD pads are made from a materiel which can act as a brake disc 1 for brake disc 1 pads of the disc brake assembly to clutch the CLD pads thus constituting the outermost surfaces of the brake disc 1 on each side surface of a brake disc 1 part placed between the CLD pads.

[0100] An advantage of providing more than one CLD pad may be that one CLD pad may be made for damping noise within one spectrum of sound waves and another CLD pad may be made for damping noise with another spectrum of sound waves.

[0101] Fig. 6A and Fig. 6B show a sixth embodiment of a brake disc, where a CLD pad (not visible) is placed between two parts of only a part of the brake disc. In the embodiment shown, the CLD pad is placed between a part of the brake disc constituting the inner section 2, that is, the hub of the brake disc, and a part of the brake disc constituting the middle section 5, that is, the spokes of the brake disc. The CLD pad has a shape corresponding to both the inner section 2 and the middle section 5 of the brake disc. Between the parts 2,5 constituting the inner section and the middle section, the CLD pad is placed, and the two parts 2,5 with the CLD pads placed between the two are mutually joined by an adhesive. The two parts and the CLD pad there-between together constitute both the inner section 2 of the brake disc and the middle section 5 of the brake disc.

[0102] Subsequently, the outermost ends of the spokes are mutually joined, by means of rivets 15 or bolts, to an innermost part of the outer section 8 constituting the brake surface of the brake disc by means of the rivets or bolts extending through holes 21 in the outer section 8 and through corresponding holes 22 in the outermost ends of the spokes 6.

[0103] Thereby, the parts 2,5 of the brake disc and the CLD pad, together with the outer section 8 constitute a brake disc as such, where the CLD pad is an integrate part of the brake disc, initially during and subsequently after manufacture of the brake disc. The CLD pad is not a separate pad attached to the brake disc subsequently to manufacture of the brake disc as in the previous figures, apart from Fig. 5, where the CLD pad also is an integrate part of the brake disc, initially during and subsequently after manufacture of the brake disc.

[0104] In the embodiment shown in Fig. 6A and Fig. 6B, a CLD pad (not visible) is placed between two parts of only a part of the brake disc, which two parts are constituting the inner section 2, that is, the hub of the brake disc, and a part of the brake disc constituting the middle section 5, that is, the spokes of the brake disc.

[0105] In an alternative embodiment to the embodiment shown in fig. 6A and 6B, a CLD pad (not visible) is placed between only one part of the brake disc, which one part is constituting the outer section 8, that is, the brake surface of the brake disc. The CLD pad then has a shape corresponding to the outer section 8 of the brake disc.

[0106] Between the parts constituting the outer section 8, the CLD pad is placed, and the part 8 with the CLD pads placed between the two are mutually joined by an adhesive. The two parts and the CLD pad there-between together constitute both the inner section 2 of the brake disc and the middle section 5 of the brake disc.

[0107] Subsequently, the outermost ends of the spokes are mutually joined, by means of rivets 15 or bolts, to an outermost part of the spokes 6 constituting the middle section 5 of the brake disc by means of the rivets or bolts extending through holes 21 in the outer section 8 and through corresponding holes 22 in the outermost ends of the spokes 6. Thereby, the part 8 of the brake disc and the CLD pad, together with the inner section 2 and middle section 5 constitute a brake disc as such, where the CLD pad is an integrate part of the brake disc, initially during and subsequently after manufacture of the brake disc. The CLD pad is not a separate pad attached to the brake disc subsequently to manufacture of the brake disc as in the previous figures, apart from Fig. 5, where the CLD pad also is an integrate part of the brake disc, initially during and subsequently after manufacture of the brake disc.

[0108] The viscoelastic layer may be provided with an adhesive intended for attaching the CLD pads 10,11 to the hub 3 and / or to the spokes 6 and / or to the outer section 8 of the brake disc 1. The viscoelastic layer, when attached to the hub 3 or the spokes 8 of the brake disc 1, is intended for transferring vibrations, induced during braking, from the outer section 8, that is the brake surface, of the brake disc 1 to the metallic layer, thereby providing squeal attenuation. The viscoelastic layer, when placed between metallic layers of the hub 3 or the spokes 6 or the outers section 8 of the brake disc 1, is intended for reducing vibrations, induced during braking, from the outer section 8, that is the brake surface, of the brake disc 1 to the metallic layer placed on each side of the viscoelastic layer, thereby providing squeal attenuation.

[0109] The CLD pads 10,11 may be made from only one metallic layer and one viscoelastic layer or possibly made from more metallic layers and / or more viscoelastic layers, respectively. If the CLD pads 10,11 are made from more than one metallic layer and / or more than one viscoelastic layer, the layers are provided alternating, that is, a metallic layer is bonded to two viscoelastic layers, one viscoelastic layer on each side surface of the metallic layer, and / or a viscoelastic layer is bonded to two metallic layers, one metallic layer on each side surface of the viscoelastic layer.

[0110] The following graphs show test results with a brake disc with CLD pads as shown in Fig. 1A and Fig. IB attached. The brake disc is for a bicycle and has an outer diameter of 160 mm. The test results show that the CLD pads result in a reduction of squeal noise compared to the same brake disc not having CLD pads.

[0111] Transfer function with and without CLD pads:

[0112] Damping ratio evaluated at eigenfrequencies:

[0113] Vehicle test without CLD pads:

[0114] During vehicle tests with CLD pads it was not possible to induce noise.

Claims

CLAIMS1. Anti-squeal pad for a brake disc (1) of a disc brake assembly for lightweight vehicles, the anti-squeal pad comprising a constrained layer damping pad (10,11,15,16,19,20) with at least one metallic layer and at least one viscoelastic layer, and the pad having a shape configured to a selected section of a shape of the brake disc (1) onto which the pad is to be attached, the shape of the pad being at least one of the following shapes:- a shape of an inner section (2) of the brake disc, the shape of the pad as the inner section (2) of the brake disc (1) corresponding to the inner section (2) outside possible holes (4) for attaching the brake disc (1) to a wheel of the lightweight vehicle,- a shape of an inner section (2) of the brake disc, the shape of the pad as the inner section (2) of the brake disc (1) having holes (14) corresponding to holes (4) of the brake disc (1) for attaching the brake disc (1) to a wheel of the lightweight vehicle,- a shape of a middle section (5) of the brake disc, the middle section (5) extending between the inner section (2) and an outer section (8) of the brake disc, the outer section (8) of the brake disc constituting a brake surface of the brake disc (1)- a shape of an outer section (8) of the brake disc, the outer section (8) extending circumferentially along an outside circumference of the middle section (5), the outer section (8) of the brake disc constituting a brake surface of the brake disc (1).

2. Anti-squeal pad according to claim 1, where at least part of the pad has an elongated shape with a first dimension (B) corresponding to a radial extension of a spoke (6) of the brake disc (1) corresponding to a radial extension of the spoke (6) of the brake disc (1) from a centre (A) of the brake disc (1) and towards an outer section (8) of the brake disc (1), the first dimension (B) of the pad being between 25 mm and 200 mm, possibly between 25 mm and 75 mm, possibly between 50 mm and 100 mm.

3. Anti-squeal pad according to claim 1 or 2, where at least part of the pad has an elongated shape with a second dimension (C) corresponding to a tangential extension of a spoke (6) of the brake disc (1) between a leading edge (6A) of spoke (6) and a trailing edge (6B) of the spoke (6), the second dimension (C) of the pad being between 3 mm and 50 mm.

4. Anti-squeal pad according to any of the preceding claims, where at least part of the pad has a geometrical shape corresponding to a shape of a spoke (6) of the brake disc (1), the geometrical shape of the pad being shaped to align with at least part of a leading edge (6A) of the spoke (6) and at least part of a trailing edge (6B) of the spoke(6), the leading edge (6A) and the trailing edge (6B) of the spoke (6) extending between an inner section (2) of the brake disc (1) and an outer section (8) of the brake disc (1).

5. Anti-squeal pad according to any of claims 1-4, where at least part of the pad has a star-like shape with first and second dimensions corresponding to a radial extension (B) of spokes (6) from the centre (A) of the brake disc (1) and towards the outer section (8) of the brake disc (1) and a tangential extension (C) of the spokes (6) of the brake disc (1) between the leading edge (6A) and the trailing edge (6B) of the spokes (6), respectively, and where- at least part of the pad has a third extension corresponding to a radial extension of inner section (2) of the brake disc (1) and to a circumferential extension of the inner section (2) of the brake disc (1),- the radial extension (B) being between 25 mm and 200 mm, possibly between 25 mm and 75 mm, possibly between 50 mm and 100 mm and the tangential extension (C) being between 3 mm and 50 mm, and- the third dimension of the pad having a radial extension corresponding to a radial extension of at least part of a hub which the pad is intended to be attached to, the third dimension being between 10 mm and 50 mm.

6. Anti-squeal pad according to claim 1, where at least part of the pad has a disc-like shape with dimensions corresponding to both a radial extension of spokes (6) of the brake disc (1), between the inner section (2) and the outer section (8) of the brake disc (1),- the pad having a radial extension (B) between 25 mm and 200 mm, possibly between 25 mm and 75 mm, possibly between 50 mm and 100 mm, and- the pad having a circumferential extension corresponding to a circumferential extension of the spokes (6) and of void spaces (5) between the spokes (6), the circumferential extension being 360 degrees.

7. Anti-squeal pad according to claim 1, where at least part of the pad has a disc-like shape with dimensions corresponding both to- a radial extension of a middle section (5) of the brake disc, the middle section (5) having an annular shape extending between the inner section (2) of the brake disc (1) and the outer section (5) of the brake disc (1) and the middle section not having spokes and not having void spaces between spokes, and- the pad having a radial extension (B) between 25 mm and 200 mm, possibly between 25 mm and 75 mm, possibly between 50 mm and 100 mm, and- the pad having a circumferential extension corresponding to a circumferential extension of the middle section (5) of the brake disc (1), preferably a circumferential extension of 360 degrees.

8. Anti-squeal pad according to claim 1, where at least part of the pad has an annular shape with dimensions corresponding to both a radial extension of the inner section (2) of the brake disc (1) and to a circumferential extension of the inner section (2) of the brake disc (1),- the pad having a radial extension between 10 mm and 100 mm, possibly between 10 mm and 50 mm, corresponding to a radial extension of the inner section (2) of the brake disc, and- the pad having a circumferential extension corresponding to a circumferential extension of the inner section (2) of the brake disc (1), preferably a circumferential extension of 360 degrees.

9. Anti-squeal pad according to any of preceding claims, where the pad has a shape as a hub (3) constituting the inner section (2) of the brake disc (1), and where the shape of the pad also has a shape of a plurality of spokes (6), preferably all spokes (6), constituting part of the middle section (5) of the brake disc (1).

10. Anti-squeal pad according to any of the preceding claims, where the pad has a shape only as a hub (3) constituting the inner section (2) of the brake disc (1), and where the pad has a shape exclusive of a shape of a plurality of spokes (6) constituting part of the middle section (5) of the brake disc (1).

11. Anti-squeal pad according to any of the preceding claims, where the pad has a shape as both the hub (3) constituting the inner section (2) of the brake disc (1) and a plurality of spokes (6), preferably all spokes (6), constituting part of the middle section (5) of the brake disc (1), and the pad also having a shape as a plurality of void spaces, preferably all void spaces, in the brake disc (1), between the plurality of spokes (6) of the brake disc (1) and also constituting part of the middle section (5) of the brake disc (1).

12. Anti-squeal pad according to any of the preceding claims, where the pad has a shape only as a brake surface (3) constituting the outer section (2) of the brake disc (1), and where the pad has a shape exclusive of a shape of a hub (5) and exclusive of a plurality of spokes (6) constituting part of the middle section (5) of the brake disc (1).

13. Anti-squeal pad according to any of the preceding claims, the pad having a plurality of holes (14) extending through the pad, the plurality of holes (14) intended for allowing bolts or rivets to pass through the pad and into a corresponding plurality of holes (4) in the brake disc (1), for attaching the brake disc (1) to a wheel of the vehicle.

14. Anti-squeal pad according to any of the preceding claims, the pad being made of at least the following layers: a metallic layer having a thickness between 0.1 mm and 6.0 mm, possibly between 0.1 mm and 3.0 mm or between 0.1 mm and 1.0 mm, and a viscoelastic layer having a thickness between 0.01 mm and 2.0 mm, possibly between 0.01 mm and 0.5 mm or between 0.05 mm and 0.2 mm,- the metallic layer intended for facing away from the brake disc, compared to an orientation of the viscoelastic layer, when the pad is attached to the brake disc, and- the viscoelastic layer intended for facing towards the brake disc, compared to an orientation of the metallic layer, when the pad is attached to the brake disc.

15. Anti-squeal pad according to any of the preceding claims, where the viscoelastic layer consists of at least two components configured as individual component layers of the viscoelastic layer, the at least two component layers being a first layer of an adhesive material and at least one second layer of a material selected among an elastomeric material and an adhesive material, and the first layer of adhesive material intended for being attached to the metallic layer of the brake disc when the pad is attached to the brake disc, and the at least one second layer intended for facing away from the metallic layer of the brake disc when the pad is attached to the brake disc.

16. A brake disc for a lightweight vehicle, the brake disc (1) having a hub (3) along an inner section (2) of the brake disc (1), spokes (6) extending between the hub (3) and an outer section (8) of the brake disc (1), and the brake disc (1) having an anti-squeal pad (10,11,15,16,19,20) with at least one metallic layer and at least one viscoelastic layer, the at least one viscoelastic layer, and the anti-squeal pad, by means of the viscoelastic layer, attached to an outer surface of one of the following sections of the brake disc (1): At least part of the inner section (2) or at least part of the middle section (5) or at least part of both the inner section (2) and the middle section (5).

17. A brake disc according to claim 16, where at least part of the pad has an elongated shape with a first dimension (B) corresponding to at least part of a radial extension of a spoke (6) of the brake disc (1) from a centre (A) of the brake disc (1) and towards the outer section (8) of the brake disc,- the first dimension of the pad being between 25 mm and 200 mm, possibly between 25 mm and 75 mm, possibly between 50 mm and 100 mm.

18. A brake disc according to claim 16 or 17, where at least part of the pad has an elongated shape with a second dimension (C) corresponding to at least part of a tangential extension of a spoke (6) of the brake disc (1) between a leading edge (6A) of the spoke (6) and a trailing edge (6B) of the spoke (6), the second dimension (C) of the pad being between 3 mm and 50 mm.

19. A brake disc according to any of claims 16-18, where at least part of the pad has a geometrical shape corresponding to at least part of a shape of the inner section (2) of the brake disc (1),- the geometrical shape of the pad having a radial extension corresponding to at least part of a radial extension of the inner section (2) of the brake disc (1), and- the geometrical shape of the pad having a circumferential extension corresponding to at least part of a circumferential extension of the inner section (2) of the brake disc (1).

20. A brake disc according to any of claims 16-19, the brake disc (1) having a hub (3) along an inner section (2) of the brake disc (1), spokes (6) extending between the hub (3) and an outer section (8) of the brake disc (1), and the brake disc having an antisqueal pad (10,11,15,16,19,20) with at least one viscoelastic layer, the at least one viscoelastic layer being placed on at least one of the following sections of the brake disc (1): the inner section (2) or the middle section (5).

21. A brake disc for a lightweight vehicle, the brake disc having a hub (3) along an inner section (2) of the brake disc (1), a middle section (5) extending between the hub (3) an outer section (8) of the brake disc (1), at least part of the brake disc (1) being made by at least the following layers:- a first metallic layer having a thickness between 0.1 mm and 6.0 mm, possibly between 0.1 mm and 3.0 mm or between 0.1 mm and 1.0 mm,- a viscoelastic layer having a thickness between 0.01 mm and 2.0 mm, possibly between 0.01 mm and 0.5 mm or between 0.05 mm and 0.2 mm, and- a second metallic layer having a thickness between 0.1 mm and 6.0 mm, possibly between 0.1 mm and 3.0 mm or between 0.1 mm and 1.0 mm, and- where the viscoelastic layer is placed between the first metallic layer and the second metallic layer.

22. A brake disc according to claim 21, the brake disc (1) having a hub (3) along an inner section (2) of the brake disc (1), spokes (6) extending between the hub (3) and an outer section (8) of the brake disc (1), and the brake disc having an anti-squeal pad (10,11,15,16,19,20) with at least one viscoelastic layer, the at least one viscoelastic layer being placed between two metallic layers of at least one of the following sections of the brake disc (1): the inner section (2) or the middle section (5).

23. A brake disc according to claim 21-22, the brake disc (1) having a hub (3) along an inner section (2) of the brake disc (1), spokes (6) extending between the hub (3) and an outer section (8) of the brake disc (1), and the brake disc having an anti-squeal pad (10,11,15,16,19,20) with at least one viscoelastic layer, the at least one viscoelastic layer being placed between two metallic layers of the outer section (8) of the brake disc (1).

24. A brake disc according to any of claims 21-23, the middle section (5) of the brake disc having one of the following shapes: a plurality of spokes (6) extending between the inner section (2) and an outer section (8) of the brake disc (1) and a plurality of void spaces between the spokes (6), or an annular shape extending between the inner section (2) and the outer section (5) of the brake disc (1) and exclusive of spokes and void spaces between spokes.

25. A brake disc according to any of claims 21-24, where at least part of the pad has an elongated shape with a first dimension (B) corresponding to at least part of a radial extension of a spoke (6) of the brake disc (1) from a centre (A) of the brake disc (1) and towards the outer section (8) of the brake disc (1), the first dimension (B) of the pad being between 25 mm and 200 mm, possibly between 25 mm and 75 mm, possibly between 50 mm and 100 mm.

26. A brake disc according to any of claims 21-25, where at least part of the pad has an elongated shape with a second dimension (C) corresponding to at least part of a tangential extension of a spoke (6) of the brake disc (1), between a leading edge (6A) of spoke (6) and a trailing edge (6B) of the spoke (6), the second dimension (C) of the pad being between 3 mm and 50 mm.

27. A brake disc according to any of claims 21-26, where at least part of the pad has a geometrical shape corresponding to at least part of a shape of the inner section (2) of the brake disc (1),- the geometrical shape of the pad having a radial extension corresponding to at least part of a radial extension of the inner section (2) of the brake disc (1), and- the geometrical shape of the pad having a circumferential extension corresponding to at least part of a circumferential extension of the inner section (2) of the brake disc (1).

28. A brake disc according to any of claims 21-27, the pad has a geometrical shape corresponding to at least part of both a shape of the inner section (2) of the brake disc (1) and a shape of each of the spokes (6) of the brake disc (1) and a shape of the outer section (8) of the brake disc (1),- the geometrical shape of the pad being shaped to extend between at least part of a leading edge (6A) and at least part of a trailing edge (6B) of at least some of the spokes (6), the leading edge (6A) and the trailing edge (6B) of the spoke (6) extending between an inner section (2) of the brake disc (1) and the outer section (8) of the brake disc (1), and- the geometrical shape of the pad also being shaped to extend radially and circumferentially along at least part of the inner section (2) of the brake disc (1), and- the geometrical shape of the pad also being shaped to extend radially and circumferentially along at least part of the outer section (8) of the brake disc (1).

29. A disc brake assembly for a lightweight vehicle, the disc brake assembly having a brake caliper with brake pads and a brake disc, the brake pads intended for clutching a brake section of the brake disc during braking, and the brake disc (1) having an antisqueal pad attached to at least one of the following sections of the brake disc (1): At least part of the inner section (2), or to at least part of the middle section (5), to both at least part of the inner section (2) and at least part of part of the middle section (5), or to at least part of the outer section (8), or to both at least part of the inner section (2) and at least part of part of the middle section (5) and at least part of the outer section (8).

30. A lightweight vehicle with at least one wheel and having at least one disc brake assembly according to claim 29 with the brake disc attached to the at least one wheel.

Images